Traffic signaling system



p 1 w. s. HALSTEAD 2,255,055

TRAFFIC SIGNALING SYSTEM Filed Marh s, I 1939 5 Sheets-Sheet 1 m In WILLIAM S. HALSTEAD INVENTOR ATTORNEY 7 Sept. 9, 1941. D

w. s'. HALSTEAD Filed March 8, 1939 5 Sheets-Sheet 3 I N I I I E v w. I

l I WILLIAM S.HALSTEAD F|G.-6

mvgmon ATTORN'EY Sept. 9, 1941. w. s. HALSTEAD TRAFFIC SIGNALING SYSTEM Filed March 8, 1959 5 Sheets-Shet 4 novous TO REMOTE CONTROL POINT FIG. 9

WILLIAM S.HALSTEAD INVENTOR BY & I ATrQRNY PL 1941- w. s. HALSTEAD 2,255,055

TRAFFIC SIGNALING SYSTEM Filed March 8, 1959 5 sheets-$516655 :l]: osc

TIMER w v no vou's 7 -u-s so sxemu. cmcunu-s "sToP" SIGNAL cmcun' z 3 x 'x 1 1 1 w CONTROL um: T0 LINE T0 SIGNAL LIGHTS RADIO TRANSMITTER FIGJO WILLIAM s. HALIfiTEAD Patented Sept. 9, 1941 I :HUNITED A S E s PATENT-L-OFFICE V TRAFFIC SIGNALING SYSTEM 'William S. Halstead, Huntington, N. Y assignor. of one-third to John B. Brady, Washington,

Application March 8, 1939, Serial No;260,644

Claims.

This invention relates in general to trafiic signaling systems and is more particularly concerned with means for efiecting traflic signaling by radio and electro-acoustical apparatus.

It is a primary object of this invention to provideradio and electro-acoustical means whereby aural control signals, trafiic bulletins or other intelligence may be transmitted at given zones changes in the signaling characteristics of a visibletrailic control system. I f

, It is an additional object of my invention to provide aradio traflic Signaling system which may be utilized by drivers of vehicles equipped with conventional broadcast. receiving equipment.

Other and further objects reside. in the constructional and circuit arrangements for efiecting coordinated operation of radio and electro-acoustical apparatus .with' traffic control means as set forth in th specification hereinafter following and by reference to the accompanying drawings in which: Y

. Figure 1 is ventional street traflic control light with supporting structure showing" attached thereto radio and electro-acoustical apparatus employed in transmitting control signals and other intelligence to motorists and pedestrians at timed intervals as determined by the operating cycle of the'a ssociated traflie control light; Fig. 2 is a front elevational' view of the. interior of a metal case shown on the traflic light support of Fig.1

airont elevational view of a congcombinatlon of radio and electro-acoustic equipment with a vehicular trafiic signaling circuit;- Fig. dis a plan view in schematic form showing a preferred system of buried cables employed as wave-guides or.transmission lines in conveying signal energy to vehicles in given traffic lanes; Fig. '7 is afront elevational view of a conventional traflicsignalJWith its supporting structure showing attached -thereto a radio transmitter and radiating structure for transmitting radio traffic control signals from a remote central control point to vehicles on the route associated with said traffic signal; Fig. 8 is a side 'elevational view of 'the radio transmitting device shown in Fig. '7;

Fig. 9* is a schematic diagram showing connections of the transmitter of Figs. 7 and 8 with the power, and control circuits provided for operation ofthe trailic light. Optional connections of an amplifier. and loudspeaker are also. indicated; and Fig. 10 is a schematic diagram illustrating interconnections at a central point of traific signal control devices, tone generator and repeating sound record machine with control circuits leading to the remote transmitter installed in proximity to a lane. of traific.

Referringto the drawings in detail, wherein like referenqecharacters indicate corresponding parts throughout the several .views, each form of the invention illustrated herewith in Figs. 1; to 5 embodies the combination of a smallradio transmitter i0, Fig.2, an-automaticrepeating sound said case containing radio and repeating sound record apparatus employed in the system of the invention; Fig. .3 is a plan. view of 'a preferred form of sound recording and reproducing ,mia-

chine enclosediir the lower-section of the case shown in Fig. 2: Fig. i is a side elevational viewof yexternal traflic-"light through transmission of a record machine H, such as a magnetic tape or wire recorder of the endless loop type, an amplifier, l2, and downwardly-directed loud speaker [3, all associatedand interconnected with the tra mc control system ofwhich visual signals ll, l5,-1l6and ,l l are a part. Each form of the invention described herewith likewise illustrates the use oi-a traflic controltone generator such as audio {frequency oscillator 45, Fig. 5, which may be correlated 'as shown with the operation of a .conventipn'al street or railway traffic control system-to provide within a. vehicle aural indication of 'the partic i lar signaling characteristic of the predetermined tone signal. l

In the particular embodiment oithe invention shown in Figs.'1 to 5; inclusive, the radiotransmitter ll), of any well'known-type having a power output of several-watts at-a selected frequency such as 550 kilocycles is disposed in a weatherproof steel case 3, preferably located on traflic light stanchion lQ,f'Fig.'"1-, or othersupport in proximityto a laneoi' "49. Magnetic tape machine II and amplifier I! may alsobe enclosed inthesameeaseasshown. I

A present preferred form of construction of the magnetic tape soimd record machine is shown in Figs. 2 and 3 in' which two rollers or cylinders 20 and II, fabricated of Bakelite or othersimilar material are horizontally disposed between bearings in frame 22, Fig. 3. Two steel tapes or wires 33 and 23A,,which serve as sound record carriers are helically wound around the two rollers. to form separate sections as shown. The firstand last loops of tape 23 are joined together over cross-over rollers or wheels Hand 25 thereby forming an endless loop. The first and last loops of tape 23A are ioinedin' similar manner over cross-over rollers 24A and 15A; Recording and a pick-up leads 26'and 28A are'disposed midway on the cross-over loops of tapes. and 23A and are supported in position by bracket 21. Electricmotor 28, Fig. 2, drives roller 2| by means of her is connected to the speech input circuit of transmitter II. The coil of relay I2 is connected through electrical time switch 33 of any wellknown type to circuit 40 which controls relay 41 and green light ll disposed so as to control ten orflfteen secondsin advaneeof a changeof lightfromgreentored. Thesameacoustlcal method may also be employed in conveying emerf netic tape machine may be instantly changed and a new recording made at the transmitting location by a patrolman with a small microphone 1 a belt 'or'chain 2!, thereby moving tapes 23 and,

vehicular tramc in lane 40, Pig. 6. Relay 32 also controls the operation of motor 20. In this manner, when the armature of relay 32 is drawn to the left hand transmitting position the magnetic tape machine is automatically started and a brief trafilc bulletin, detour instruction warning, light change warning, or other intelligence is transmitted by radio to drivers of vehicles proceeding on lane 40 during a predetermined interval while the green light 4| is in operation.

When power isremoved from green light circuit a relay. 12 returns to the right-hand position shown in Pig. 5. In the open position, control arm it breaks the circuit to motor 20 which remains inoperative until power is again applied through closure of relay II. In like manner the magnetic tape machine may be coordinated with the red light circuit 02, if desired, to permit transmission of a given message to vehicles while waiting for a traffic signal to change from red to green.

Pick-up coil ll of head 10A is connected through contact arm ll of relay ll to the input circuit of amplifier "A, the output circuit of which is connected to loud s er l3. Relay I0 is connected through time switch 31 to circuit 10 which controls operation of relay 41A and green' light Tl of intersecting lane II, Fig. 6. Power is applied to motor 28 through closure of contact arin I! of relay." when in the left-hand operating position. In this manner, at a predetermined time interval, such as ten or fifteen sec onds, before a givensignal changes from green to red, relay It is closed by operation of time switch 31. Thus the magnetic tape machine is started and pick-up coil 34 is connected to the input circuit of amplifier IIA. Loud speaker I! is thereby energized and conveys brief safety messages or other intelligence addressed to pcdestrians at main. trafllc intersections. By this methodpedestrians about to cross a main thoroughfare at a dangerous intersection may be t given an aural warning such as Do not cross Broadway now. The light is about to change" green light ll for radio transmission to vehicles by connection of the output circuit of an audio frequency oscillator I! to the input circuit of amplifier l2 and by connections with relay M in the control circuit as shown in broken ling in Fig. 5; Contact arm ll of relay 32 is connected to condenser C2 disposed in the oscillating circuit of the tone generator 40. The contact arm of relay, is connected in left-hand position to con-' denser Ci and in the right-hand position to condenser Ca, both disposed in the oscillating circuit of tone generator 45. Thus when red light control circuit 42 is energized closure of relay 44 places condenser C1 in the oscillating circuit of the tone generator, producing a characteristic stop tone of frequency Fr such as 4000 cycles for transmission to vehicles approaching a red light in lane 49. Opening of relay 44 by removal of energizing current in red light circuit 42 eifacts movement of the armature of relay II to the right-hand position. Condenser C: is there- 'by placed in the oscillating circuit to produce a characteristic "go tone of frequency F3, such as 200 cycles. Energization of green light control circuit 40 initiates the control cycle of timer 03 which after a predetermined interval clams relay 32 and thereby moves contact arm 48 to the left placing condenser e: ml the oscillating circuit of tone generator 45. during a short period imm a change from green to red tely in advance of li ht may thus be a given a characteristic caution tone of frequenahead to the driver of a vehicle even though he I may not be ableto see the light in questionbecause of obstructions in his path or for other reasons. In addition, the tones may be employed to control the operation of signal lights disposedwithin the vehicle, said lights being selectively energized by connections with the output circuit of a radio receiver having frequency discriminating devices attached thereto as is described in United States Patent No. 2,131,042, granted Seprelated with the operation of red light' band The emitted 818 181 ployed as is illustrated in Fig. 6, for installations tember 27, 1938, and in pending applications Serial Numbers 228,051 and 228,052, filed Septemher 1, 1938.

It is pointed out that the circuit of Fig. 5 illustrates means for coordinating radio and electroacoustical equipment with operation of traffic signals disposed to control trafiic in a given lane such as north-south street 49, Fig. 6, or a particular railway track in the application of the. system ot the invention to railway signaling. To control traflic in another lane, such as east-west street 66, or a parallel railroad track carrying trafllc in an opposite direction a second radio transmitter IDA with similarly coordinated equipment is employed.

Radio signal energy from transmitter I 00-- operatively associated with trafhc lights 46 and 4| in lane 49 may be conveyed to vehicles proceeding in a given traflic control zone .up to several thousand feet in length by means of cable or cables 5| disposed in the traflic lane as shown in Fig. 6, or otherwise disposed in proximity thereto. Radio signal energy from transmitter |0A by similar means 52 is conveyed to vehicles proceeding in intersectinglane 50. To prevent cross-talk between adjacent transmission circuits one frequency such as 550 kilocycles may be emin which a range of several thousand feet is required. i

Power for the radio transmitter is obtained by connection with existing power circuit 66 employed to energize the associated trafllclights such as 40 and 4|, Fig. 9. Relays 43 and 41 by means of. light control circuits 42 and 46 respec- ,tively select for energization lights 46 and 4|,

ployed for one lane-such as'49, and a slightly different frequency such as 560 kilocycles may be employed for intersecting or difierent lanes.

Radio frequency energy is transferred from the radio transmitter to the cable 5| by employing any well-knowncoupling means which permits of extremely loose coupling between the output circuit of thetransmitter and the cable conductor. Satisfactory results have been attained in practice by connecting one end of a coil of several turns, not shown, to the cable conductor, said coil being disposed adjacent to the antenna loading circuit of the transmitter at a distance suflicient to reduce the coupling to the point where the cable may be attached or. detached from its coil without causing any appreciable change in the plate current of the output stage of the transmitter. In this manner, through limitation of the amount of signal energy carried by the cable to an extremely small value the transmit-' ted signal cannot efiectively be heard until an approaching vehicle is within approximately a hundred feet of the cable, though a strongand substantially uniform signal is received while the vehicle is proceeding along the cable.

Selection of a particular frequency for use within a given geographical zone is dependent on existing assignments to other services. 550

within a given zone is posted in proximity to the lane of traflic as shown in Fig. 1, wherein a small sign 53 is disposed on the traffic light housing.

In a modification of the system shown in Fig. 7 a waterproof metal case, 54, enclosing a, low power transmitter 56, Fig. 9, is mounted on traffic light stanchion l9, Fig. 8, adjacent to a lane of tramc 49. A radiating element 55, Fig. 9, in the form of a rod or coil, protected by a tubular housing 57, Fig. 8, is employed to transmit signal energy to vehicles within several hundred feet of said transmitter. A cable 5| may also be en:-

eflected in step with changes in the trailic signals a diagram of a simplified control circuit is shown in Fig. 10 wherein a timer 65 of any con-,

ventional type is employed to actuate a relay 64 which in turn efiects energization of stop signal circuit 42 or go signal circuit 46. Connections of the relay 64 are such that when'the armature is in the position shown in Fig. 10 contact arm 63 closes against the right-hand contact thereby applying an E. M. F. from battery 66.1;0 green light control circuit 46. At the same time, tone control arm 61 places condenser C2 in the oscillating circuit of the audio frequency wave generator 59 thus producing control tone F2 associated with green light 4|. When the armature of relay 64 moves to the left-hand position circuit 42 associtrol '61 moves against its associated lefthand contact thereby inserting C1 into the oscillating circuit, of wave generator 59 to produce a' control tone F1, associated with red light 40.

The control tones correlated with each signal are amplified by vacuum tube amplifier 68 and thereafter transmittedby line 6| or by duplex operation over light-control circuits 42 and 46 to the input circuit of transmitter 56, from which point the control signals are transmitted to vehicles. The pick-up coil 69 associated with the recording and reproducing head of the magnetic tape machine 60 is connected to a separate input channel of amplifier 68 as shown.

Timing of transmissions from the steel tape unit may be efiected by means of'operation of relay 16 connected with time switch 65 through circuit 1|. Thus at a. predetermined time interval coordinated with the trafllc light control cycle aural bulletins from magnetic tape machine 66 may be-transmitted.

It is pointed out that while this specification has described an application of the system of the quency. Thus the engineer of a train. on a northbound track, for example, will receive the signal from the proper transmitter without interference from the transmitter tuned to a different frequency intended for signaling to southbound trains. Such a system may readily be applied in practice because of the present availability of satisfactory crystal-control transmitters having a high degree of frequency stability, and receivers of the push-button type, which permit convenient and accurate tuning change from one given frequency to another without possibility of error.

It will be recognized that the illustrative systems described herein are capable of considerable modification and rearrangement without depart ing from'the spirit and scope of the invention, and it is therefore to be understood that the following claims embrace all such modifications and equivalent arrangements as may fairly be construed to fall within the scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. In a traflic signaling system, a transmitter for emitting a carrier frequency efiective substantially within a predetermined zone along a traflic lane to effect automatic communication with vehicular traflic moving in said zone in said traflic lane, a sound storage device having a recorded message thereon for effecting continuous automatic repetition of a given communication addressed to traffic in said predetermined zone, means for modulating said carrier frequency by said sound record storage device, the time for the transmission of said complete recorded message being not greater than the normal time required for a vehicle to negotiate said predetermined zone.

2. A trafiic signaling system having a radio transmitter to eifect automatic communication with vehicular traffic moving in a given traffic lane, a signal record device for effecting continuous automatic repetition of a given communication addressed to traffic in said trafiic lane, means for modulating said radio transmitter by said signal record device, and a transmission line disposed substantially parallel to said traflic lane for the purpose of limiting the eifective signalling area to a desired trafiic signaling zone, the time for the transmission of said complete communication being not greater than the normal time required for a vehicle to fully negotiate the signaling zone..

3. In a traffic signaling system, a transmitter for emitting a carrier frequency effective substantially within a predetermined zone along a tranic lane to effect automatic communication with vehicular traflic moving in said lane, a sound storage device having a recorded message thereon for effecting continuous automatic repetition of a given communication addressed to traflic in said predetermined zone, means for modulating said carrier frequency by said sound storage device, visual right of way indicating means, means for operating said last mentioned visual means to alternately indicate stop and go signals to traflic in said predetermined zone, and means for synchronizing the transmission of said recorded message through .said transmitter with the operation of said visual stop and go right of way indicating means.

4. A traffic signaling apparatus for controlling the flow of traflic in a traflic lane and having, in

combination, visual right of way indicating means.

to alternately indicate stop and go signals to traffic in said trafllc lane, a timer for controlnals, switching means controllable lay said timer for energizing the stop and go signals, a

source of carrier wave energy, means for emitting said carrier wave energy eifective substantially within a predetermined zone along a trafllc lane, and means controlled by said timer for modulating said carrier wave in accordance with a plurality of frequencies, two of said frequencies representing stop and "go" indications coordlnated with said stop and go visual indications respectively.

5. In a trafll'c signaling system, a transmitter for emitting a carrier frequency effective substantially within a predetermined zone along a trafilc lane to effect automatic communication with vehicular traillc moving in said zone in said traflic lane, a sound storage device having a recorded message thereon for effecting contin-- uous automatic repetition of a give communication addressed to trafli'c in said predetermined zone, means for modulating said carrier frequency by said sound storage device, the time for the transmission of said complete recorded message being not greater than the normal time required by a vehicle to negotiate said predeter-' mined zone, and a visible marking device placed ahead of said signaling zone and adjacent thereto for the purpose of advising tramc of the presence and frequency of said transmitter.

6. In a traflic signaling system, a transmitter for emitting a carrier frequency effective substantially within a predetermined zone along a trafiic lane to effect automatic communication with vehicular traffic moving in said zone in said traffic lane, a sound storage device having a recorded message thereon for effecting continuous automatic repetition of a given communication addressed to traflic in said predetermined zone, and means for modulating said carrier frequency by said sound storage device, said last mentioned means including an amplifier, and a pick-. up device connected to the input of said ampli- '7. In a traflic signaling system having visual stop and go indicators, a timer for'controlling the sequence and duration of operation of said stop and go indicators in a signaling cycle, switching means controlled by said timer for energizing said stop" and "go indicators, 9. source of carrier wave energy, signal emitting means connected to said source of carrier wave energy and being disposed to emit signaling energy within a restricted zone along a traflic lane in which the flow of traflic is controllable by said visual stop and go indicators, a source of audio frequency energy, and a second switching means controlled by said timer for varying the frequency of said audio frequency energy in definite predetermined steps, one of said steps having a predetermined audio frequency characteristic correlated with said stop indicator, a second of said steps having a predetermined audio frequency characteristic correlated with said go indicatonand a third of said steps having a predetermined audio frequency characteristic corresponding to a caution" indication.

8. In a traflic signaling system as set forth in claim 6, in which the sound storage device includes a magnetic tape and the pick-up device includes a pick-up coil for reproducing signals impressed on said magnetic tape.

9. In a traffic signaling system having visual stop and go indicators, timing means for controlling the sequence and duration of operation of said stop" and go" indicators in a signaling cycle, switching means controlled by said timing means for selectively energizing said stop and go" indicators, a source of audio to said source of. wave energy, directional signal frequency wave energy, an amplifier connected I transmission means connected to said amplifier for efiecting directional transmission of signal energy within a predetermined signaling zone along a trafilc lane and a second switching means controlled by said timing means for varying the frequency of said source'\ of audio frequency wave energy in definite predetermined steps, one step being correlated with the operationof said step indicator, and a second step being correlated with said go indicator.

10' In a trafllc signaling system having visual stopi nd go indicators, timing means for controlling the sequence and duration 'of said stop and go indicators in a signaling cycle, switching means controlled by said timing means for selectively energizing said stop" and "go" indicators, a sound record device having a magnetic tape, a pick-up head disposed in proximity to said tape, an amplifier connected to said pickup head, directional signal transmission means connected to said amplifier for eflecting directional transmission of signal energy within a predetermined signaling zone along a traiiic lane, and a second switching means controlled by said timing means for efiecting transmission of intelligence as pie-recorded on said magnetic tape in timed correlation with the selective operation or said visual stop and go indicators.

. WILLIAM S. HALS'I'EAD. 

